Glass-melting pot



L. SHOWERS GLASS MELTING POT Filed Nov. 3

Patented Apr. 15, 1930 UNITED STATES PATENT OFFICE LEE SHOWERS, F CHARLEROI, PENNSYLVANIA, ASSIGNOR TO PITTSBURGH PLATE GLASS COMPANY, A'GORPORATION OF PENNSYLVANIA h GLASS-MELTING POTc Application led November 3, 1927. Serial No. 230,817.

. The invention relates to a glass melting pot. The invention has for its obiects the pro- Vision of a poured pot, (1) which can be arched or burned without cracking without the exercise of any special care or precautlon, (2) which will give long service, be- Cause of its ability lto stand the strains im.- posed in handling and which at thev same 'timeis very resistant to corrosion by the material gives a supporting body which will 1 molten glass, and (3) which has the foregoing desirable characteristics even with the largest size pots, which have hitherto been regarded as impracticableto make by a pouring operation. Brieiy stated, this result is secured by pouring the pot in two layers., both made from the same batch, but the inner one being composed of materials which are more finely ground than ,those used in the outside layer. The more finely ground material g1ves greater resistance to the corrosion of the -tus employed,V 1s preferably that shown and glass than the more coarsely ground material, while the outer layer of more coarsely ground stand the strains imposed by handling better than themore linely divided material and whichl will not crack in firing, as is apt to occur with a pot composedl entirelyof the finely divided material,- unless unusual care is observed in ring or arching.

The material of he two layers, being of the same batch, have the same amount of expan. -sion under heat and show no tendency to separate under the most severe conditjons of use.

The vbatch employed may vary between certain limits, but preferably comprises the following approximate proportions:

140? raw 'clay (mixed. ball and kaolin c ays 30% sand (part coarse and part fine).

30% pot shell (or other burned clay).

These materials are ground and mixed with water and a deflocculating agent, whereby a maximum degree of fluidity may be secured with a minimum amount of water. The deiiocculating agents employed are preferably gallic acid, caustic soda and sodium silicate, as set 'forth in the Fulton Patent No. 1,398,011, of Nov. 22, 1921, but .other agents may be used if desired. The use of these agents g1ves a screen having mesh openings about one fourth inch in diameter, while for the inside layer, theyare ground so that the coarsest particles will pass through a screen wherein 1 'I l -the openings are about one seventh of an 1nch in diameter, but it will be understood thatl these dimensions vmay vary within reasonable limits depending upon conditions. The pot Sand the method of making it'are illustrated in the drawings, wherein:

Figs.l 1 to 4 are vertical sections showing the successive steps incident to the formation of the pot.- And'Fig. 5 is a vertical section l through the' pot.

In carrying out the operation, the apparadescribed in the Fulton Patent No. 1,364,875 of Jan. 11,1925. An amount of Huid mix 1 is placed in the mold 2'carried upon the truck 3 and a plunger forced down into themix to cause it toassume the shape 4 of Fig. Q, the

4plunger being left in position until the clay sets, thus forming the outer layer of the pot. As heretofore' explained, the mix in this case is made from the more coarsely ground material or batch.

The -mix or batch made from the more plunger-s are constructed and operated, as described in the Fulton ,Patent No. 1,364,875 heretofore referred to andy comprise an outer facing 7 of plaster of Paris and an inner wood support or core 8 of wood, the'plunger being forced down by the rods 9, 9 and lifted by the bail 10. Y The plunger is left in position until thc layer 6 sets, after 'which it is removed aud the pot'removed on the truck 3 to the drying room where the outer mold 2 is removed and linely ground batch is now placed in the Viis the pot is allowed to dry out during a long period the usual way preliminary to ring Y l or arching.. f

Fig. 5 shows-the complete pot with the walls or layers 4 and 6 of the same batch com osition, except as to the fineness with which the materials are ground, the inner layer being of finer grain than the outer yone and more resistant to corrosion. The two layers of clay apparently weld to ether or at least form a very close union an no separation occurs either in theiiring or arching of the pots preliminary to usin them, or in the u`se\ofV the pots in melting giss.` Pots of the largest size for the manufacture of plate ,glass are made in this way, at a much lower cost than the regular plate glass pots fabri- 'cated bythe laborious hand method heretofore used, and give the'same or better service. The pots are apparently as strong as the hand made pots, 'can be arched or burned without diiiculty, and are very resistant to corrosion by the molten glass, so that the quality of the glass produced compares favorably with that of the hand madey pots. The` thickness of the walls of this pot at the rim (for plate glass work) is about the same as in the ordinary hand made pot, which is about ...four inches. The outer layer 4 is shown as thicker than the inner one, but they may be made lof the same thickness. Good results have been obtained with an outer wall' three inches in thickness with an inner wall one inch in thickness, and also in pots wherein both walls were two inches in thickness. In

A the pot as illustrated, the thickness of the walls, in proportionto the other. dimensionsof the pot as shown, is rmuch exaggerated.

What I claim is: 1. A poured glass melting pot of clay com- 'tion comprising an outer layer and an inner layer both of substantially the same batch except that the materials of the inner .layer are more finely ground than those ofthe outer layer.

2. A poured glass melting pot of clay composition comprising an outer layerand an inner layer both of substantially the same batch except that the materials of the inner layer are more finely ground than those of the outer layer, such materials including raw clay and burned clay. l

3. A poured glass melting pot of clay composition comprising an outer layer and an inner layer both of substantially the same .batch except `that the materials of the inner layer are more finely ground than those of the outer la er, such materials including raw claly, burne clay and iinel divided silica.

n testimony whereof, I ave hereunto subscribed my name-this 29 day of September,

y LEE SHOWERS. 

